1. Field of the Invention
This invention relates to modified electrodes their manufacture and use, to electro-release systems including such electrodes for electro-release of compounds, for example medical or veterinary pharmaceutical compounds, and to methods for electro-release. By electro-release is meant that the electrochemical release of the compound, or the inhibition of such release, is caused by the application of an appropriate voltage bias to an electrode. Such a system allows accurate control of timing and/or amount of release.
2. Description of Prior Art
A naked electrode placed in a conducting solution can be viewed as an infinite sink or source of electrons which behaves as a tunable redox reagent. The rate of oxidation or reduction of molecules close to the electrode can be controlled by varying the interfacial electrode potential. In this way reactions can be switched on or off. Some twenty years ago it was recognised that chemical modification of an electrode surface with functional groups may provide additional degrees of control over the electrochemistry. The types of control sought include: chiral induction, whereby a prochiral molecule is reduced or oxidised to a single optical isomer; electrocatalysis, whereby electron-transfer chemistry is catalysed by binding substrate molecules at catalytic sites; electro-releasing, whereby electrode-bound molecules are released into solution by changing the electrode potential; and electrosensing, whereby selective interaction of an analate with the modified surface gives rise to a measurable electrode response. The design and construction of devices based on modified electrodes have potential application in areas such as controlled drug delivery, bioelectrocatalysis and bioelectronics.
There have been some previous published proposals for an electro-release system. The present inventors have published details of modified electrodes in publications listed at the end of this description.